1. Field of Invention
The present invention relates to inducing flow of venous blood in a patient's limb from the lower portion of a limb to an upper portion of the limb proximal the patient's heart relative the lower portion.
2. Prior Art
In U.S. Pat. No. 4,702,232 by Gardner and 4,841,956, a division thereof, there is recited a method of a pump-actuating sequence which characterizes normal walking. This is accomplished by sequentially applying pressure to the foot, the proximal calf and then to the distal calf in repeating cycles.
There is a definite disadvantage in the prior art method of inducing venous flow of the blood by first compressing the foot, in that a sharp impact has to be made at the sole of the foot so the blood from the foot is forced into very compliant leg veins. Sufficient blood is forced from the foot to form a bolus of blood. As the bolus of blood moves up the veins in the limb its bulk dilates the veins beyond there normal elasticity. This excessive dilation may cause damage to the walls and lining of the veins. Additionally, the energy to move the blood up the limb is absorbed by dilating the veins so that velocity decreases as the bolus moves up the limb. Because of this diminshed velocity, only a slight increase in velocity may be seen at the knee and little or none may be seen at the thigh. This not only minimizes the systemic effectiveness of this kind of compression, but may cause damage to the veins of the patient because of the increase in the distention of the veins.
The above prior art method may also result in potential deep vein thrombosis and pulmonary embolism due to damage done to the lining of the veins.
The conditions created by the prior art are not conducive to healing of a patient or the prevention of deep vein thrombosis (DVT) and should be avoided.
The present invention provides a more advanced method in obtaining effective and excellent enhanced transmitting of blood through the venous system. This advanced method minimizes excessive distention of the veins and any potential for deep vein thrombosis and pulmonary embolism which the prior art method has not.